Download or read book Polymer Induced Drag Reduction Based on Stress Relaxation written by Susan Mary Lemke Penix and published by . This book was released on 1987 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Various Aspects of Polymer Induced Drag Reduction in Turbulent Flow written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Drag Reduction by Surfactant Additives written by Feng-Chen Li and published by John Wiley & Sons. This book was released on 2012-01-10 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent drag reduction by additives has long been a hot research topic. This phenomenon is inherently associated with multifold expertise. Solutions of drag-reducing additives are usually viscoelastic fluids having complicated rheological properties. Exploring the characteristics of drag-reduced turbulent flows calls for uniquely designed experimental and numerical simulation techniques and elaborate theoretical considerations. Pertinently understanding the turbulent drag reduction mechanism necessities mastering the fundamentals of turbulence and establishing a proper relationship between turbulence and the rheological properties induced by additives. Promoting the applications of the drag reduction phenomenon requires the knowledge from different fields such as chemical engineering, mechanical engineering, municipal engineering, and so on. This book gives a thorough elucidation of the turbulence characteristics and rheological behaviors, theories, special techniques and application issues for drag-reducing flows by surfactant additives based on the state-of-the-art of scientific research results through the latest experimental studies, numerical simulations and theoretical analyses. Covers turbulent drag reduction, heat transfer reduction, complex rheology and the real-world applications of drag reduction Introduces advanced testing techniques, such as PIV, LDA, and their applications in current experiments, illustrated with multiple diagrams and equations Real-world examples of the topic’s increasingly important industrial applications enable readers to implement cost- and energy-saving measures Explains the tools before presenting the research results, to give readers coverage of the subject from both theoretical and experimental viewpoints Consolidates interdisciplinary information on turbulent drag reduction by additives Turbulent Drag Reduction by Surfactant Additives is geared for researchers, graduate students, and engineers in the fields of Fluid Mechanics, Mechanical Engineering, Turbulence, Chemical Engineering, Municipal Engineering. Researchers and practitioners involved in the fields of Flow Control, Chemistry, Computational Fluid Dynamics, Experimental Fluid Dynamics, and Rheology will also find this book to be a much-needed reference on the topic.

Download or read book Analytical and Experimental Study of Turbulent Flow Drag Reduction and Degradation with Polymer Additives written by Xin Zhang and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow friction reduction by polymers is widely applied in the oil and gas industry for flow enhancement or to save pumping energy. The huge benefit of this technology has attracted many researchers to investigate the phenomenon for 70 years, but its mechanism is still not clear. The objective of this thesis is to investigate flow drag reduction with polymer additives, develop predictive models for flow drag reduction and its degradation, and provide new insights into the drag reduction and degradation mechanism. The thesis starts with a semi-analytical solution for the drag reduction with polymer additives in a turbulent pipe flow. Based on the FENE-P model, the solution assumes complete laminarization and predicts the upper limitation of drag reduction in pipe flows. A new predictive model for this upper limit is developed considering viscosity ratios and the Weissenberg number - a dimensionless number related to the relaxation time of polymers. Next, a flow loop is designed and built for the experimental study of pipe flow drag reduction by polymers. Using a linear flexible polymer - polyethylene oxide (PEO) - in water, a series of turbulent flow experiments are conducted. Based on Zimm's theory and the experimental data, a correlation is developed for the drag reduction prediction from the Weissenberg number and polymer concentration in the flow. This correlation is thoroughly validated with data from the experiments and previous studies as well. To investigate the degradation of drag reduction with polymer additives, a rotational turbulent flow is first studied with a double-gap rheometer. Based on Brostow's assumption, i.e., the degradation rate of drag reduction is the same as that of the molecular weight decrease, a correlation of the degradation of drag reduction is established, along with the proposal of a new theory that the degradation is a first-order chemical reaction based on the polymer chain scission. Then, the accuracy of the Brostow's assumption is examined, and extensive experimental data indicate that it is not correct in many cases. The degradation of drag reduction with polymer additives is further analyzed from a molecular perspective. It is found that the issue with Brostow's theory is mainly because it does not consider the existence of polymer aggregates in the flow. Experimental results show that the molecular weight of the degraded polymer in the dilute solution becomes lower and the molecular weight distribution becomes narrower. An improved mechanism of drag reduction degradation considering polymer aggregate is proposed - the turbulent flow causes the chain scission of the aggregate and the degraded aggregate loses its drag-reducing ability. Finally, the mechanism of drag reduction and degradation is examined from the chemical thermodynamics and kinetics. The drag reduction phenomenon by linear flexible polymers is explained as a non-spontaneous irreversible flow-induced conformational-phase-change process that incorporates both free polymers and aggregates. The entire non-equilibrium process is due to the chain scission of polymers. This theory is shown to agree with drag reduction experimental results from a macroscopic view and polymer behaviours from microscopic views. The experimental data, predictive models, and theories developed in this thesis provide useful new insights into the design of flow drag reduction techniques and further research on this important physical phenomenon.

Download or read book Polymer Induced Drag Reduction in Exact Coherent States of Plane Poiseulle Flow written by Wei Li and published by . This book was released on 2007 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drag Reduction by Dilute Polymer Solutions in Turbulent Flow written by Ralph C. Little and published by . This book was released on 1967 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism by which water-soluble polymers reduce hydrodynamic drag on solid surfaces was investigated by measurements of flow birefringence and of turbulent flow in pipes. Flow birefringence and flow field orientation of Polyox polymers in the molecular weight range from 200,000 to 6,000,000 showed that Polyox macromolecules continue to deform with increasing velocity gradient even after alignment with the flow field (at gradients in excess of 2000/sec). All solutions used were found to be Newtonian, with the exception of the AcrysolA-5 solutions. The flow data for Polyox solutions in a Pyrex pipe were examined in terms of Meyer's fluid property parameter and Elata's relaxation time hypothesis for the initiation of drag reduction. It was found that drag reduction in the Pyrex pipe was initiated at a value of the order of one-fifth that predicted by Elata's theory. Moreover, added salt (the solution being 0.3 molar in K2SO4) had no effect on the flow of Polyox Coagulant solutions even though the intrinsic viscosity (upon which Rouse relaxation times depend) was cut to slightly more than one-third of its value in the pure solvent. The unusually high values of Meyer's fluid property parameter observed at low concentrations suggests that adsorption on the Pyrex pipe walls may be playing a role in drag reduction. (Author).

Download or read book Correlation of Drag Reducing Data in Dilute Polymer Solutions written by Jorge Mario Rodriguez and published by . This book was released on 1966 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The purpose of this investigation was to obtain a correlation for drag reducing solutions in circular tubes under turbulent conditions. Data were taken for three polymer-solvent systems: polymethyl methacrylate V-100 (M[subscript v] ~ 110,000) in toluene, polyisobutylene L-200 (M[subscript v] ~ 4,700,000) in toluene, and polyisobutylene L-200 in cyclohexane. The data from the two polyisobutylene systems, together with other data on polymethyl methacrylate G (M[subscript v] ~ 1,500,000) in toluene and polyisobutylene L-80 (M[subscript v] ~ 860,000) in cyclohexane, were used to attempt to obtain the correlation. The V-100 solutions were not used because they were not drag reducing. The variables that were believed to affect drag, reduction were considered and three dimensionless groups were used as the correlating groups. These groups were: a generalized Reynolds Number (N[subscript Re]' ), a Deborah Number, which is the ratio of the relaxation time of the polymer molecules to a characteristic flow time of the system, and a friction factor ratio. Two different characteristic flow times were used: D/V and n/T[subscript w],which gave rise to two Deborah Numbers. Also, three friction factor ratios were considered. The data were studied by plotting two of the groups and using the third one as a parameter. Several concentrations of each polymer-solvent system were studied individually and the relationships obtained were compared to attempt to obtain a correlation independent of concentration....Several methods for predicting friction factors with some accuracy were developed, but these methods only applied to a given concentration of a system. A relationship between a modified shear stress and velocity that applied to all concentrations of a polymer-solvent system was also obtained, but this method- does not allow accurate predictions of pressure drops"--Abstract, pages vii-viii.

Download or read book The Drag Reduction of Dilute Polymer Solutions as a Function of Solvent Power Viscosity and Temperature written by Paul Peyser and published by . This book was released on 1971 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The frictional drag reduction of high-molecular-weight polyethylene oxide and polystyrene solutions under turbulent flow conditions was studied as a function of temperature, solvent power, and solvent viscosity. A rotating disk apparatus was used to make the drag reduction measurements. For aqueous polyethylene oxide solutions, at concentrations well above that needed to produce maximum drag reduction, all drag reduction data reduced to a common curve when percent drag reduction was plotted against the Reynolds number for the flow. However, for polyethylene oxide solutions below this optimum concentration the drag reduction-versus-Reynolds number curves showed decreasing drag reduction with increasing temperature. The data are explained primarily in terms of the inverse temperature solubility characteristics of polyethylene oxide in water. The percent drag reduction of polystyrene in nonaqueous liquids was found to be greater in good solvents than in poor ones. It was also found that increases in solvent viscosity and decreases in temperature increased the percent drag reduction. The results are discussed in relation to the current drag reduction theories and are shown to be in opposition to Virk's theory. It is concluded from the data that drag reduction is very likely a function of a relaxation time phenomenon involving the polymer molecules and the flow system. The results also emphasize the importance of considering solvent power, viscosity, and temperature in the design of an efficient drag reduction system. (Author).

Download or read book Investigations on Drag Reduction by Interactions Between Polymer and Surfactant and Polymer and Polymer written by Jia Yang and published by . This book was released on 2015 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large amount of studies have been carried out on pipeline flow with several kinds of drag reducing agents, especially polymers and surfactants. Drag reducing agents, by definition, are additives which help suppress or eliminate turbulence in a pipeline. The mechanism and methodology of polymer only or surfactant only as drag reducing additives have been fully discovered. Whether mixed drag reducers such as polymer-surfactant or polymer-polymer systems would be effective is still not clear. In our study, polymer-surfactant and polymer-polymer mixed additives are used in order to explore the synergistic effects and interactions in pipeline flow loops. The experimental work was divided into two sections: bench-scale experiments and pilot-scale experiments. In bench-scale experiments, the properties of prepared fluids such as, surface tension, conductivity and shear viscosity were measured. Several comparison methods and calculations were applied to give better understandings of the properties resulting from mixing of polymer with surfactant and polymer with polymer. After analysis of the properties, several combinations of concentrations were selected and solutions were prepared in the main tank of pilot plant and pumped into the pipeline set-up to test the pipeline flow behaviors. Turbulence structure/Reynolds number, pipe diameter, polymer-surfactant concentration were all considered as influencing factors. Critical micelle concentration, critical aggregation concentration, polymer saturation point, the onset of drag reduction, and the interactions between the mixed additives were discussed. A comparison between pipeline results and the predictions of Blasius Equation or Dodge-Metzner Equation were also discussed.. For polymer-surfactant studies, a commonly used polymer additive - carboxylmethylcellulose (referred to as CMC which is anionic) was selected as the drag reducing agent. The performance of this polymer was investigated in the presence of six surfactants respectively - Alcohol ethoxylate (referred to as Alfonic 1412-9 and Alfonic 1412-3 which are nonionic), Aromox DMC (nonionic surfactant), Stepanol WA-100 and Stepwet DF-95 (which mainly consist sodium lauryl sulfates, anionic surfactant) and Amphosol (which is zwitterionic).The experiments were first conducted with pure CMC solution with different concentrations (100ppm, 500ppm, 700ppm and 1000ppm) as a standard. The 500ppm CMC solution was selected as the best polymer concentration with highest drag reduction efficiency. For polymer-surfactant combinations, CMC-Alfonic 1412-9, CMC-Alfonic1412-3, CMC-Stepanol and CMC-Stepwet systems were found to have significant interactions. High surfactant concentration resulted in reduction in %DR. The addition of Aromox increased the drag reduction ability and onset point when concentration was higher than the polymer saturation points. Also, both hydrophobic and electrostatic interactions were thought to have an effect on critical micelle concentration, which led to the fluctuations in the %DR. For polymer-polymer studies, PAM-PEO system at two different polymer concentrations were investigated. Overall, Pure PAM solution had much higher drag reduction ability than pure PEO solutions. Mixing them together, strong interactions occurred when PEO fraction was high (over 50%) which affected %DR and shear viscosity substantially. Power-law constants n and k were also taken into account and found to exhibit opposite trends with the increase of PEO fraction.

Download or read book Drag Reduction and Shear Degradation of Dilute Polymer Solutions as Measured by a Rotating Disk written by T. T. Huang and published by . This book was released on 1972 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A saturated drag-reduction line for dilute polymer solutions is derived for a rotating disk from new velocity-similarity laws. Drag reduction measured by a rotating disk is found to have three domains--oversaturated, optimal and undersaturated. At a given boundary-layer thickness and wall-shear stress, the drag-reduction increases with increasing concentration in the undersaturated domain, and the drag reduction does not increase with increasing concentration in the oversaturated domain. The boundary between the two domains is the optimal drag reduction, which is determined by the type of polymer and its concentration and a Reynolds number based on shear velocity and disk radius or boundary-layer thickness. (Author).

Download or read book Properties and Behavior of Polymers 2 Volume Set written by Wiley and published by John Wiley & Sons. This book was released on 2012-12-03 with total page 1605 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides comprehensive, up-to-date information on the physical properties of polymers including, viscoelasticity, flammability, miscibility, optical properties, surface properties and more. Containing carefully selected reprints from the Wiley's renowned Encyclopedia of Polymer Science and Technology, this reference features the same breadth and quality of coverage and clarity of presentation found in the original.

Download or read book Drag Reduction by Polymer Addition written by Marten T. Landahl and published by . This book was released on 1972 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Special attention is paid to the changes in turbulence structure brought about by polymer additives, and an effort is made to understand these in the light of recent advances in the study of shear flow turbulence in ordinary fluids. Also a simplified theoretical model of shear flow wall turbulence is presented, with the aid of which an exploratory study of the influence of some non-Newtonian fluid properties is carried out. A particularly intriguing feature is the remarkable effectiveness of extremely high-molecular-weight polymers by which only a few parts per million of weight of solvent are sufficient in some cases to lead to drag reductions of 50 per cent or more. (Modified author abstract).

Download or read book Drag Reduction in Newtonian Polymer Solutions written by Harry C. Hershey and published by . This book was released on 1965 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Prior work in the area of drag reduction has been mainly limited to aqueous solutions. Theoretical and empirical analyses of the resulting data in aqueous solutions have been hindered by the fact that some polymers cause drag reduction and others do not...This investigation was directed to the study of how the size and configuration of the polymer molecule in solution affected drag reduction and the related phenomenon of turbulence suppression. Apparatuses were designed and built to measure viscometric flow, curves, friction factors, velocity profiles, and normal stresses (by a jet thrust technique developed by Metzner and associates)"--Summary, leaves 1-2.

Download or read book Achieving Drag Reduction Through Polymer surfactant Interaction written by Anosh Mevawalla and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Drag reduction is a well-observed phenomenon, it was first observed by the British chemist Toms in 1946, yet its mechanism is still unknown to this day. Polymer Drag reduction has found application in reducing pumping costs for oil pipelines (its use in the Trans Alaska Pipeline has resulted in an increase from 1.44 million bbl./day to 2.1356 million bbl./day), increasing the flow rate in firefighting equipment, and in supporting irrigation and drainage systems. Surfactant drag reducers are used industrially in district heating and cooling systems. Though the fields of Surfactant Drag Reduction and Polymer Drag Reduction are each independently well-developed the effect of their interaction on drag reduction is a less explored phenomenon. Through a well chosen pairing of surfactant and polymer, drag reduction can be maximized while minimizing surfactant and polymer concentrations cutting down on cost and environmental impact. The focus of this work was to determine if there was any positive interaction between the polymers Polyethylene Oxide (PEO) and Anionic PolyAcrylAmide (PAM) and the surfactant Amphosol CG (Cocamidopropyl Betaine) as well as any interaction between the polymers themselves. Both polymers are popular drag reducers while Amphosol is a practically nontoxic (LD50=5g/kg) zwitterionic surfactant and is readily biodegradable. In order to determine if any interaction was present and at what concentration was this most notable 4 techniques were used: Surface tension, Conductivity, Relative Viscosity and Shear Viscosity measurement. From this analysis the polymer Saturation point (PSP), Critical aggregation concentration (CAC) and Critical micelle concentration (CMC) were found as well as the concentrations that optimized the viscosity for the pilot plant runs. The bench scale results were used to pick the optimum concentrations for the polymer surfactant solutions. Pressure readings and flowrate measurements were used to plot the Fanning Friction Factor against the Generalized Reynolds Number for the surfactant polymer mixtures and compared to their pure polymer and surfactant counterparts. The Blasius line was found to hold for water measurements taken and is the base to determine percentage drag reduction. The effect of the presence of amphosol on degradation and overall drag reduction were noted. Other factors considered were pipe diameter and the effect of ionic impurities in the solvent.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drag Reduction in Pipeline by Polymer surfactant and Polymer polymer Mixtures written by Weicong Huang and published by . This book was released on 2015 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive researches have been conducted to investigate into the drag reduction behavior of the polymer-surfactant mixture and the polymer-polymer mixture. The drag reduction effect of PAM (polyacrylamide), PEO (polyethylene oxide) and CMC (carboxymethyl cellulose) has already been studied respectively. However, the drag reduction effects of the combination of these polymers have not been studied before. It is interesting to investigate into these combinations because the synergy between different polymers can enhance the drag reduction effect under the right condition. SDS (sodium dodecyl sulfate) is a surfactant widely used in many commercially available detergents. When dissolved in water and circulated in the flow loop, the drag reduction effect of SDS has also been observed. Therefore, the combination of PAM and SDS is also worth exploring. The synergy between the polymer and the surfactant may strengthen the drag reduction effect. In this thesis, the drag reduction effects are investigated for the following combinations: the PAM-SDS system, the PAM-CMC system and the PEO-CMC system. The mixed solutions are circulated in the flow loop, where the pressure drop over a certain distance and the flow rate are recorded in order to plot the friction factor against the Reynolds number. In addition, the viscosity, conductivity and surface tension of the mixed solutions are studied at bench-scale to look for the synergy in the mixed system.

Download or read book Drag Reduction Using Novel Polymer Complexes written by William Daures and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: